| 摘要 |
PURPOSE:To reduce the current consumption of a memory system or the like using lots of memory chips by controlling a power supply voltage by a chip select signal so as to reduce the current consumption at the chip non-selecting state. CONSTITUTION:A chip select signal CS' turns to a low level at chip selection and a P-channel MOS transistor (TR) P1 is turned on. Thus, an internal power source VCC(I) of an internal power supply circuit 3 has a voltage nearly equal to that of an external power supply VCC. The chip select CS' turns to a high level at chip non-selection and the TR P1 is cut off. Thus, the voltage of the internal power supply is VCC(I)=VCC-m(Vth) and the voltage is lower than the voltage of the external power supply VCC, where Vth is a threshold voltage of N-channel MOSTRs N1, N2-Nm. |
